1. Field of the Invention
The present invention relates to an electrical connector for receiving a removable integrated circuit card and for making electrical contact with integrated circuit elements supported within the card.
2. Description Relative to the Prior Art
An integrated circuit card encloses one or more integrated circuit elements mounted on a substrate and connected to an electrical contact pattern toward one end of the card. A shutter is provided to cover and protect the contact pattern when the card is removed from an electrical connector and to expose the contact pattern for electrical connection when the card is inserted into the connector. The contact pattern is ordinarily delicate and must be protected against unusual contact force. On the other hand, a good electrical connection requires a positive contact between the contact pattern and contact electrodes in the connector.
The contact electrodes are frequently spring-loaded elements. It is difficult, however, to accurately locate and tension the electrodes so that the card can be easily inserted and reliable contact established. As a result, relatively complex solutions are sometimes seen in the prior art. For example, in U.S. Pat. No. 4,801,272, the contact electrodes are initially withdrawn from the connector and then pivoted into the connector by association with a spring-loaded lever that is driven into motion as a card is inserted. In U.S. Pat. 4,724,310, the contact electrodes are located on a block that is mounted on a carriage for movement along a floor of a card receptacle between a waiting position to an operating position in which the electrodes are moved up against the card. In U.S. Pat. 4,652,976 the electrodes remain fixed in place and, instead, the integrated circuit card is physically moved after insertion. The card is inserted onto a guide plate that rotates the card toward a press-contact type connector. Consequently, the contact pattern on the memory card never slides over the electrodes in the connector.
The conductive contacts of the contact pattern are on a part of the substrate that is accessible to the electrical connector. The necessary force exerted by the electrodes to effect reliable contact with the substrate contact pattern can wear the contacts after repetitive insertion and removal of the card. Electrical signals are then not properly transmitted. The above-cited patents address this problem as a by-product of electrode movement, that is, the electrodes are physically brought into contact with the pattern after, or in conjunction with, the process of insertion, thereby reducing wear on the contacts. These systems are, however, characterized by relatively complex mechanical or electro-mechanical assemblies for providing electrical connection without causing damage to the pattern during the insertion process.